Strange Sounds

Arkansas1

Past Arkansas Chapter Leaders
I am a new owner to a 2008 3670RL:D , It's a great looking rig and looks even better behind my 2001 F-250 7.3 Lariet "Platinum Edition", however since after the third or forth time out on the road, my wife and I noticed an unusual sound comming from what appears to be from the rear of the truck, the sound noticed is like when someone runs over a rumble strip.
When this sound was heard I checked under the truck and could not find signs of rubbing or wear, I have however noticed that when it does make the sound, it is when I start from a stopped position and then goes away once in motion, obviousley very concerned:confused: .

hog wild
 

Arkansas1

Past Arkansas Chapter Leaders
I am not sure? This is the first time that this has occurred since I purchased the Big Horn, but I have considered the axle as a source, of the sound.
Thanks for the input it helps me to narrow down the possibilities:rolleyes: .
Mike
 

jpmorgan37

Well-known member
Mike;

Check the drive shaft and u-joints too. Do you know what your pin weight is? You are putting a lot of load on that F-250 and may be torquing the differential when you start off. I will bet the it is exceeding the GVWR of the truck. I've been there.

John
 

Arkansas1

Past Arkansas Chapter Leaders
John, the best I can make if I am reading my information correctly is 1,990 pin weight. I can only hope that I am not going over and causing additional problems.
Thanks for your response.
Mike
 
John, I had a similar problem with by f-250 it sounded like a dump truck was coming up beside me and only when I let up on the gas, Unfortunate it required a new rear end.
 

madigand

Well-known member
I would suspect the rear end/u-joints as jp morgan suggested. These are heavy units and have a high pin weight.

FYI, we are full timing in ours and this is our weight

Truck (no trailer attached)

Front axle 4940 gawr 6000
Rear axle 4060 gawr 9000

Truck and Trailer

Front Truck axle 4980
Rear Truck axle 7360
Trailer axels 12820 (7k axels)

Total weight 25160
Pin weight 3300

As you can see I am under my weights. It is heavy at 16,100. I have the tow command and not had any problems so far. But it is heavy and if you stop on a dime you get no change back. I generally leave some extra space when traveling as a cushion factor. Hope this helps
 

jpmorgan37

Well-known member
Mike;
Unless you are super heavy in the rear of your coach and have helium bags in the front, I question your 1990 pin weight. I am running over 3000 on my pin and I'm not the exception. There are a lot of post, including weights from our rally last year, that give pin weights and most are mid 2000's to low 3000. A few months ago, I posted a chart for determining axel weight and pin weight. It's easy to do and will take less than a half hour on the scales, if you can find someone to work with you. I would try feed stores or recycle stations that have a scale. Even highway weigh stations will do it, if they are not busy with trucks.

John

John
 

Arkansas1

Past Arkansas Chapter Leaders
John, as you can tell I am new to 5th wheeling, and I am learning as I go, it certainly is different from the 30' travel trailer we had for several years. We do have a weight station near-by and I will take it this week and get the weights that I need and see if I can make heads or tails of it, Nikki & Harry appreciate the input, I also thought of the axle, but am hoping that it won't be, but I suppose that it could be worse!
Thanks for all of your input and suggestions, your assistance is making the transition form travel trailer too 5th wheeler a bit easier!
Mike
 

jpmorgan37

Well-known member
Mike;

One of the beauties of the Heartland Owners Forum is the many experienced folks who can help answer most of the questions that we have. I have gotten a so much help from many of the members. Enjoy your new coach and welcome to the Heartland family.

John
 

Arkansas1

Past Arkansas Chapter Leaders
John,
Thanks for the welcoming to the family of heartland owners, we are looking forward to meeting with as many members as we can in the future!
Betty and I are about to take an over night trip to Branson, Missouri . Where I beleive that the group will be visiting next June, so I'll check my messages later.
Mike
 

kakampers

Past Heartland Ambassador
John,

That 1,990 pin weight is DRY...we have the 3600 and our actual pin weight is 3,940lbs...a very big difference! I would venture to say you are quite a bit over on your RAWR. You might want to hit a scale and check your actual weights against the recommended weight ratings. I can bet you will be surprised...quite possibly unpleasantly!
 

Loco

Well-known member
The first question would be does your truck set down with the trailer on it. If it does then the this could be caused by the drive line angle being changed. Our new F-350 does this some and only does it starting off with the trailer. I am going to put air bags on our rig to keep it level when towing. This will stop the drive line virbrations. Ford said that this happen on some of there trucks when loaded heavy. I have also talked to a friend that is into hot rod diesel pickup trucks and he works for a shop that builds up these big pickups and he also said it most likely the drive line angle. This is not always true, but if it does it only when the truck is loaded and the rear end is set way down on to the helper springs. This would be the first thing to look into.
 

WRIGHT ll

retired Oklahoma Chapter Leaders
Mike, it sounds like a u-joint but if you have a limited slip rear end it might be the culprit. I have a buddy who never serviced his until it made a really bad noise and after it was properly drained, flushed and refilled along with the correct additive it got quiet again.
 

Arkansas1

Past Arkansas Chapter Leaders
Thanks for the input, I have an appointment to have the rear end checked, and I am taking the rig and truck to the scales to see what kind of weights I actually have. I am running bags on my F-250 so I am hoping that the truck is operating as level as possible, however I am going to recheck and make sure, I do appreaciate all of your help and input.
Mike
 
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